Chestnut plant named ‘AU Buck II’

ABSTRACT

‘AU Buck II’ is a new and distinct Chinese chestnut cultivar that is blight resistant, precocious and prolific. It produces a large nut. Nut drop begins about September 15 and continues for a 6–7 week period. A large percentage of the nuts drop during the first three weeks after the beginning of nut drop. ‘AU Buck II’ nuts mature and start dropping during the early phase of the normal ripening period that most Chinese chestnut cultivars mature and drop nuts in the area. ‘AU Buck II’ is a large tree that was 9.14 meters tall, with a canopy area of 101.36 square meters at 15-years of age. ‘AU Buck II’ is the second cultivar to mature and drop nuts in a series of four Chinese chestnut cultivars that will provide for a continuous nut drop of a high energy wildlife food source from late August through mid-to-late November.

Latin name of the genus and species of the plant claimed: Castaneamollissima Blume.

Variety denomination: ‘Au Buck II’.

BACKGROUND OF THE INVENTION

A Chinese chestnut planting was established at Auburn University,Auburn, AL, from nuts collected in China. The planting was establishedon the United States Department of Agriculture Horticulture Farm whichin later years became the Mainstation Horticulture Farm. Precocious andprolific-bearing, blight resistant seedlings were selected for nutappearance, size and quality. Each generation of seedlings were theproduct of controlled mass pollination from the most promising seedlingsselected from the previous generation. ‘AU Cropper’, ‘AU Leader’ and ‘AUHomestead’ were released from a second generation of approximately 2000seedlings. A planting of third generation seedlings from controlled masspollination of ‘AU Leader’, ‘AU Homestead’ and ‘AU Cropper’ wasestablished at the Auburn University Piedmont Substation at Camp Hill,AL.

SUMMARY OF THE INVENTION

‘AU Buck II’ is an open pollinated seedling of ‘AU Homestead’.

The present invention relates to a new and distinct Chinese chestnutcultivar that is blight resistant, precocious, produces large sized nuts(16.6 g), and begins nut drop about September 15 and continues for a 6–7week period. A large percent of the nuts drop during the first threeweeks after nut drop begins. The nuts mature and start dropping duringthe early part of the normal ripening period for most Chinese chestnutcultivars in this area. The large crop of large sized nuts is anexcellent high energy food source for wildlife such as deer andsquirrels. The original 15-year old ‘AU Buck II’ tree is a large tree,9.14 meters tall, with a canopy width of 11.35 meters, and a canopy areaof 101.36 square meters. The tree has a trunk diameter of 37.9 cm atbreast height. The ‘AU Buck II’ produced nuts the third year aftertransplanting, has produced a large crop annually for the size of tree,and produced 127.9 kg (282 pounds) of nuts in 2006.

‘AU Buck II’ cultivar is the second cultivar to mature and drop nuts ina series of four Chinese chestnut cultivars that will provide acontinuous nut drop of a high energy wildlife food source from lateAugust through mid-to-late November. ‘AU Buck I’, ‘AU Buck III’ and ‘AUBuck IV’ are the other three cultivars, which are disclosed in U.S.patent application No. 12/012,091, filed on Jan. 30, 2008, and entitled“CHESTNUT PLANT NAMED ‘AU BUCK I’”, U.S. patent application No.12/012,110, filed on Jan. 30, 2008, and entitled “CHESTNUT PLANT NAMED‘AU BUCK III’” and U.S. patent application No. 12/012,112, filed on Jan.30, 2008, and entitled “CHESTNUT PLANT NAMED ‘AU BUCK IV’”, which arehereby incorporated by reference.

The new cultivar is able to be asexually reproduced by budding orgrafting onto a seedling Chinese chestnut rootstock. The uniquecharacteristics come true to form and are established and transmittedthrough asexual propagation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photograph of nuts of the ‘AU BUCK II’ cultivar.

FIG. 2 is a photograph of nuts of the ‘AU BUCK II’ cultivar.

FIG. 3 is a photograph of a tree of the ‘AU BUCK II’ cultivar.

DETAILED BOTANICAL DESCRIPTION

The Chinese chestnut, Castanea mollissima Blume, is a cold, hardy,temperate zone species native to China. It can be grown between 30° and50° latitudes. The Chinese chestnut is resistant to chestnut blightfungus Cryphonectria parasitica. Generally, Chinese chestnuts are grownon a wide range of soils, but well-drained, deep and fertile soils areconsidered the best. Soils should be slightly acidic with pH 5.6–6.5.The name mollissima means soft hair and this species is recognized bydense hair on young leaves and downy yellow terminal parts of the shootsin winter. The leaf blade is thicker, and, in general, mature leaves arebroader than those of other species. The nuts have a small scar orhilum. The pellicle or thin membranous skin on the nuts is thin andpeels readily from the kernel. The trees are a spreading type andlong-lived with a round top. The trees have bark with furrows and budswith 3–4 scales and leaves are 2 ranked, serrated with numerous parallelveins.

Chestnuts are monoecious and staminate flowers appear on erectcylindrical catkins with 10–20 stamens and 6-parted calyx. Pistillateflowers are borne on a lower part of the upper staminate catkins andrarely on separate catkins usually 3 in a prickly symmetrical involucrewith 7–9 styles and a 6-celled ovary. Nuts are small, brown with a palescar at the base. Generally, 1–3 nuts per involucre or bur are present.

‘AU Buck II’ is a tall tree that is obovate in shape with high, diffuseand upright branches. The original 15-year old tree is 9.14 meters(29.96 feet) tall with a trunk diameter at breast height of 37.90 cm(14.92 inches). The canopy is 11.35 meters (37.20 feet) wide and coversan area of 101.36 square meters (1091.0 square feet). The average nutlength is 30.70 mm (1.21 inches) and the average nut width is 37.70 mm(1.48 inches). The nuts start dropping about September 15 and continueto drop for a 6 to 7 week period. A large percent of the nuts dropduring the first three weeks after nut drop begins. The nuts mature andstart dropping during the early part of the normal ripening for mostChinese chestnuts cultivars in this area. ‘AU Buck II’ is a precociousand prolific fruiting cultivar.

In the planting at the Piedmont Substation, Camp Hill, AL., accurateyields could not be obtained due to extremely heavy wildlife (deer andturkey) feeding. Therefore, the trees were rated for crop load eachyear. ‘AU Buck II’ has been a producer of a large crop load each season.In the fall of 2006, individual trees were caged with 6 foot (1.83meters) tall chicken wire prior to nut drop to exclude wildlife and nutswere picked up daily during nut drop. The original 15-year old ‘AU BuckII’ tree produced 127.9 kg (282.0 pounds) of nuts in 2006. This is amuch greater yield than the yields of similar aged trees.

The table below illustrates the specific differences between the ‘AUBUCK II’ cultivar and the ‘REVIVAL’ cultivar.

The botanical details of this new and distinctive variety of chestnuttree - with color definitions (except those in common color terms)referenced to Royal Horticultural Society's Colour Chart (RHS) and colorwas also determined using an electronic spectrophotometer to determinehue angle and Chroma (spectrophotometer model CM-2002; Minolta CameraCo., Japan). 10/23 ‘AU BUCK II’ CHESTNUT Tree: Size (at maturity) -large-fifteen year old original tree is 9.14 meters tall with a canopywidth of 11.35 meters and a canopy area of 101.36 sq. meters Tree shapeis round. Vigor - very vigorous Trunk: Form - upright with branches lowand diffuse Texture - relatively smooth Color of bark - brown RHS N200B,Chroma C* 11.85, hue angle 85.23 Branches: Form - upright and spreadingTexture - relatively smooth Lenticels - few, small Branching habit - lowand spreading Color - new wood: brown, RHS 200C, Chroma C* 13.80, hueangle 71.55, mature wood: grey-brown RHS N199A Chroma C* 13.69, hueangle 91.59 Foliage: Quantity - abundant Density - dense Leaves: Size -large. Length (cm) 20.5 (17.5-23.5) [20] width (cm) 8.2 (7.2-9.3) [20]leaf ratio 2.5 (2.1-3.0) [20] Shape - oblong-elliptic to obovate leaftip - acuminate to acute leaf base - rounded; equal to obliqueThickness - thick. Leaf venation 1° pinnate: 2° ± parallel, prominentabaxially Texture - moderately coriaceous Margin - weakly to coarselyserrate; teeth ascending Petiole - length 0.9 cm (0.5-1.8) [20] Petiolepubescence - sparingly to generously pubescence of simple hairs Color -adaxial surface, glabrous blade; scattered simple hairs on main veinsmedium green; moderately shiny, RHS 147A, Chroma C* 14.62, hue angle120.75 abaxial surface, moderately to densely stellate pubescence onblade; simple hairs along main veins, RHS 147B, Chroma C* 18.44, hueangle 110.70 Bloom: Amount of bloom - heavy Color - at anthesis, 161Dgreyed-yellow group, 157D green-white group, 155C white group Bloomingperiod - mid-May. After foliation in April. Age at which tree startsflowering - early, 2-3 years alter graft replacement. Male flower -Catkin length (cm)-13.7 (11.8-15.7) [15] Male flower - stamen number percatkin-11.3 (10-12) [15] Female flower - flower number per bur - 3Female flower - style number per flower 6.7 (5-8) [12] Crop: Bearing -regular annual bearer Productivity - prolific Ripening period - long,nuts begins dropping September 14 and continues for a 4-5 week period.Distribution of nuts on tree - well distributed, fruits on terminalswith 2-4 burs per terminal. Tenacity - burs crack while on tree and nutsrelease and drop from bur. Hull: Description - spiny round bur Size -2.98-3.71″ in diameter Number of nuts - 2-3 per bur Dehiscence - splitseasily when still on tree Color - yellow-green at dehiscence, RHS N144CNut: Size - very large; average size- 1.21″ × 1.48″ × 0.81″. Averageweight - 16.6 grams 27 (23-33) nuts per pound. Form - very large,broader than long, flattened on 1 side, occ. 2, mostly hemispheric onother side; rounded basally, almost flat distally with little or no tip.Blossom end - small pointed tip Basal end - flattened Color - lightbrown, RHS 200B, Chroma C* 14.03, hue angle 40.05 Pubescence - mixedlong and short, fine, white hairs densely covering the ⅛ to ¼ end,otherwise sparse and glabrate elsewhere Shell - thin Hardness of shell -relatively hard, yet not rigid Texture of shell - smooth Percentage ofkernel to nut - very high-90-95% Kernel: Size - almost as large as nutsize Form - same as nut shape Pellicle - thin Flavor - excellent, verysweet Color - straw color, RHS 152D, Chroma C* 45.86, hue angle 81.35Resistance to insects: no unusual susceptibilities noted Resistance todisease: no susceptibilities to disease noted The chestnut tree and itsnuts herein described may vary in slight detail due to climatic and soilconditions under which the variety may be grown; the present descriptionbeing of the variety as grown in Camp Hill, Ala. The botanical detailsof this variety of chestnut tree - with color definitions (except thosein common color terms) referenced to Maerz and Paul Dictionary ofColor-are as follows: ‘REVIVAL’ Tree: Size (at maturity) - large Vigor -very vigorous Trunk: Form - upright with branches spreading in upperreaches of tree. Texture - relatively smooth Color of bark - Silvergray(13-A-1) Branches: Form - strong Texture - relatively smooth Lenticels -few, small Branching habit - spreading in upper region of tree Color -new wood: reddish brown and glossy, mature wood: silver gray Foliage:Quantity - abundant Density - dense Leaves: Size - large. Averagelength - 5-7″ (including petiole). Average width - 2″ Shape - oblongwith acute tip and rounded base Thickness - thick Texture - smoothMargin - dentate Petiole - length: medium. Thickness: medium. Color -Top side - glossy dark green (22-L-12). Under side - lighter green(21-D-7). Bloom: Amount of bloom - heavy Color - cream white (17-B-1)Blooming period - late. After leaf out in April Age at which tree startsflowering - early; 2-3 years years after graft replacement. Crop:Bearing - regular (yearly) bearer Productivity - prolific Ripeningperiod - short. September 15-October 1. Distribution of nuts on tree -well distributed Tenacity - burrs crack while on tree and nuts easilyrelease, many falling by themselves Hull: Description - spiny, roundburr Size - 3-4″ in diameter Number of nuts - 2-3 per burr Dehiscence -splits easily when still on tree. Some entire burrs split and fall toground Color - brown (15-A-8) Nut: Size - large. Average size - 1⅛″ ×1⅛″ × 1″ thick. Average weight - 24-32 nuts per pound Form - broad andovoid on one side, flat on other side Blossom end - pointed tip Basalend - flattened Color - India Red (7-L-6). Shell - thin Hardness ofshell - relatively hard, yet not rigid Texture of shell - smoothPercentage of kernel to nut - very high (95%) Kernel: Size - almost aslarge as nut size Form - same as nut shape Pellicle - thin Flavor -excellent. Very sweet. Color - Oyster white (10-B-1) Resistance toinsects: no unusual susceptibilities noted Resistance to disease: veryhigh inherent resistance to chestnut bark fungus (Endothia parastica),no other susceptibilities to any other disease The chestnut tree and itsnuts herein described may vary in slight detail due to climatic and soilconditions under which the variety may be grown; the present descriptionbeing of the variety as grown in Alachua, Fla.

‘Au Buck II’ is different from ‘AU Gobbler I’ in several ways. Forexample, the size of the trees, the trunk forms and colors, thebranches, the leaves, the crop and the nuts have differences.Specifically, the ‘AU Buck II’ tree is shorter with a canopy area largerthan the ‘AU Gobbler I’ tree. The ‘AU Buck II’ branches areupright/spreading, low/spreading and brown (new) or grey-brown (mature);whereas, the ‘AU Gobbler I’ branches are upright, high, diffuse andbrown (new) or greyed-green (mature). The leaves differ in size, shape,margin, petiole and color. The ripening period for the ‘AU Buck II’ isaround September 14 and continues for a 4–5 week period, but the ‘AUGobbler I’ ripening period is around August 25 and continues for 4–5weeks. The average weight of the nuts of ‘AU Buck II’ is 16.6 gramsversus 7.7 grams for ‘AU Gobbler I’. Furthermore, ‘AU Buck II’ hasroughly 27 nuts per pound, and ‘AU Gobbler I’ has roughly 59 nuts perpound.

‘AU Buck II’ is different from ‘AU Gobbler II’ in several ways. Forexample, the trees, the trunk colors, the branch colors, the leaves, thecrop and the nuts have differences. Specifically, the ‘AU Buck II’ treeis taller with a canopy width and canopy area larger than the ‘AUGobbler II’ tree. The ‘AU Buck II’ branches are brown (new) orgrey-brown (mature); whereas, the ‘AU Gobbler II’ branches re brown(new) or greyed-green (mature). The leaves differ in size, shape, marginand color. The ripening period for the ‘AU Buck II’ is around September14 and continues for a 4–5 week period, but the ‘AU Gobbler II’ ripeningperiod is around September 5 and continues for 4–5 weeks. The averageweight of the nuts of ‘AU Buck II’ is 16.6 grams versus 5.7 grams for‘AU Gobbler II’. Furthermore, ‘AU Buck II’ has roughly 27 nuts perpound, and ‘AU Gobbler II’ has roughly 65–101 nuts per pound.

‘AU Buck II’ is different from ‘AU Premier’ in several ways. Forexample, the trees, the trunk colors, the branch colors, the leaves, thecrop and the nuts have differences. Specifically, the ‘AU Buck II’ treeis taller with a canopy width and canopy area larger than the ‘AUPremier’ tree, The ‘AU Buck II’ has a grey-brown trunk, and the ‘AUPremier’ has a greyed-green trunk. The ‘AU Buck II’ branches are brown(new) or grey-brown (mature); whereas, the ‘AU Premier’ branches arebrown (new) or greyed-green (mature). The leaves differ in size, shape,thickness, texture, margin, petiole and color. The ripening period forthe ‘AU Buck II’ is around September 14, and the ‘AU Premier’ ripeningperiod is early September through mid-November. The average weight ofthe nuts of ‘AU Buck II’ is 16.6 grams versus 1.26 grams for ‘AUPremier’. Furthermore, ‘AU Buck II’ has roughly 27 nuts per pound, and‘AU Premier’ has roughly 360.3 nuts per pound.

‘AU Buck II’ is different form ‘AU Encore’ in several ways. For example,the trees, the trunk colors, the branch colors, the leaves, the crop andthe nuts have differences. Specifically, the ‘AU Buck II’ tree is tallerwith a canopy width and canopy area larger than the ‘AU Encore’ tree.The ‘AU Buck II’ has a grey-brown trunk, and the ‘AU Encore’ has agreyed-green trunk. The ‘AU Buck II’ branches are brown (new) orgrey-brown (mature); whereas, the ‘AU Encore’ branches are brown (new)or greyed-green (mature). The leaves differ in size, shape, thickness,texture, margin, petiole and color. The ripening period for the ‘AU BuckII’ is around September 14, but the ‘AU Encore’ ripening period is lateSeptember through late November. The average weight of the nuts of ‘AUBuck II’ is 16.6 grams versus 2.4 grams for ‘AU Encore’. Furthermore,‘AU Buck II’ has roughly 27 nuts per pound, and ‘AU Encore’ has roughly189.2 nuts per pound.

1. A new and distinct cultivar of the species Castanea mollissima Blumenamed ‘AU BUCK II’ as described and illustrated herein.